speedymopars
08-07-2007, 09:54 AM
I just bought my first boat, a 74 21 foot closed bow Cheyenne with a 455 olds and a Berkeley 12JC jet with an A impeller. The hull rides really nice, had it out at Lake Elsinore 3 x last week figuring out all what was wrong with it. This is my first Olds motor, I am a Mopar kind of guy, though I do own a 454 in my motorhome. It has a .490 lift cam, screw in valve studs, and a performer. Hardin manifolds and through transom exhaust. Twin 20 gal tanks.
The starter was dead, OK it died on the lake, so DB electric in Stanton remanufactured it (reused only the case basically) and converted it to a marine starter (added the spark arrester) for $95.
The engine idled at 1400 rpm - not the hot ticket for the docks I'd say. The carb was a 3310 with a black spring (not the hot ticket for RPM) and a std powervalve (won't work with a loper). It has a .490 lift 23x @.050 duration cam in it, so the std power valve wouldn't work. I could hit a max of 3800 RPM on the first outing. The carb was black from the backfires, and the PV was toast leaking fuel everywhere.
I took it back and modified my 850 DP for marine use (it was setup for off road use), it was already on one of my Mopars with a fairly simular cam in a 440, so dropping it on allowed it to idle down to 650 RPM with a nice lope. I had to turn the idle screw about an 1/8 of a turn, but other than that, it was dead perfect.
The valve covers were leaking, so a quick gasket cured that.
The next outing was very pleasant at the docks, 650 RPM doesn't push enough water to worry about being out of control. With the DP that was set up correctly with 3.5 pv's, it didn't load up, and the RPM's went up to 5200, which according to the berkeley specs, that is about 450 HP, give or take the wear on the pump.
The boat is in the interior shop this week getting gutted and rebuilt.
I am really good with engines, I have a lot of fast cars, but the jet, and boating is new to me. My parents had a 16ft outboat boat we would ski behind when I was 8-14, but that is the extent of my boating experiance.
My understanding of these olds motors is that they have a long stroke that gives great torque, but the massive size of the rod bearings causes them to want to spin, and the oiling "features" of this engine cause the pan to want to suck dry at sustained high RPM.
The 455 I have, according to the recipts in my possesion, has been rebuilt due to a spun rod bearing 3 times, everything is at .030 over, and the bearings show the crank has been turned 3 times too. I may be out of options for the next rebuild unless I get new parts.
My solution, and those who see my handle know what is coming next, is to use the stroker motor I have in the garage. It is a 512 c.i. Mopar big block, made from a 400 engine. This bottom end can handle around 1000 HP, and spin 9K all day long due to the extremely light reciprocating assembly. Obviously, I can cam it anyway I want, so I think I need to keep the RPM's under 6K for the jet, correct? This combo would probably be bullet proof, as the bottom end will be overkill at such low RPM's (for that motor).
I know I will need to mount the engine in the hull, most likey do a motor plate, but what do I need for the other end? Are all marine bellhousings the same, IE, an outdrive and a jet use the same marine housing or are they different? Obviously, I need to get one for a mopar, but I am clueless on the other end. What about the flywheel? The same? Different? What connects the flywheel to the jet? Some kind of driveshaft with a flange on it? CouldI potentially use what I have if I get a mopar marine bellhousing and flywheel, and do I have to get one for a jet drive, or are they all the same? I wuld assume that the parts that I need to change would be the same if I was converting to a BB Ford or Chevy.
Anyway, Thanks!
The starter was dead, OK it died on the lake, so DB electric in Stanton remanufactured it (reused only the case basically) and converted it to a marine starter (added the spark arrester) for $95.
The engine idled at 1400 rpm - not the hot ticket for the docks I'd say. The carb was a 3310 with a black spring (not the hot ticket for RPM) and a std powervalve (won't work with a loper). It has a .490 lift 23x @.050 duration cam in it, so the std power valve wouldn't work. I could hit a max of 3800 RPM on the first outing. The carb was black from the backfires, and the PV was toast leaking fuel everywhere.
I took it back and modified my 850 DP for marine use (it was setup for off road use), it was already on one of my Mopars with a fairly simular cam in a 440, so dropping it on allowed it to idle down to 650 RPM with a nice lope. I had to turn the idle screw about an 1/8 of a turn, but other than that, it was dead perfect.
The valve covers were leaking, so a quick gasket cured that.
The next outing was very pleasant at the docks, 650 RPM doesn't push enough water to worry about being out of control. With the DP that was set up correctly with 3.5 pv's, it didn't load up, and the RPM's went up to 5200, which according to the berkeley specs, that is about 450 HP, give or take the wear on the pump.
The boat is in the interior shop this week getting gutted and rebuilt.
I am really good with engines, I have a lot of fast cars, but the jet, and boating is new to me. My parents had a 16ft outboat boat we would ski behind when I was 8-14, but that is the extent of my boating experiance.
My understanding of these olds motors is that they have a long stroke that gives great torque, but the massive size of the rod bearings causes them to want to spin, and the oiling "features" of this engine cause the pan to want to suck dry at sustained high RPM.
The 455 I have, according to the recipts in my possesion, has been rebuilt due to a spun rod bearing 3 times, everything is at .030 over, and the bearings show the crank has been turned 3 times too. I may be out of options for the next rebuild unless I get new parts.
My solution, and those who see my handle know what is coming next, is to use the stroker motor I have in the garage. It is a 512 c.i. Mopar big block, made from a 400 engine. This bottom end can handle around 1000 HP, and spin 9K all day long due to the extremely light reciprocating assembly. Obviously, I can cam it anyway I want, so I think I need to keep the RPM's under 6K for the jet, correct? This combo would probably be bullet proof, as the bottom end will be overkill at such low RPM's (for that motor).
I know I will need to mount the engine in the hull, most likey do a motor plate, but what do I need for the other end? Are all marine bellhousings the same, IE, an outdrive and a jet use the same marine housing or are they different? Obviously, I need to get one for a mopar, but I am clueless on the other end. What about the flywheel? The same? Different? What connects the flywheel to the jet? Some kind of driveshaft with a flange on it? CouldI potentially use what I have if I get a mopar marine bellhousing and flywheel, and do I have to get one for a jet drive, or are they all the same? I wuld assume that the parts that I need to change would be the same if I was converting to a BB Ford or Chevy.
Anyway, Thanks!